The subject-matter of the invention is a method for manufacturing or obtaining fodder and/or soil improving agents from waste materials, for instance from environmentally disturbing aquatic plants and aquatic weeds respectively, particularly floating freshwater plants, such as specifically the water hyacinth (Eichhornia crassipes).
It has been known for a long time that aquatic weeds, such as the water hyacinth, propagate, specifically under tropical conditions, at a very fast rate, rapidly and thickly covering a large part of the water surface, which disturbs shipping, chokes up irrigation plants and affects the living conditions for fish and birds. An example hereof are the problems occurring in Egypt, where in Lake Nasser south of the Aswan Dam and in the irrigation and drainage systems, favourable conditions are created for the propagation of aquatic weeds. The propagation of these aquatic weeds is aggravated by the eutrophication of the waters caused by the intensive agriculture using high quantities of fertilizers, so that these aquatic weeds constitute an acute problem. For instance, they do not only impede the water flow through the canals, but also cause, as a result of evapotranspiration, the loss of high quantities of water, so that it is common practice to remove these materials mechanically or destroy them by means of herbicides which considerably impair the environment.
On the other hand, specifically in those areas where such aquatic weeds are able to propagate particularly intensively, as in the developing countries, or also in Egypt, there is a considerable need for animal protein which could be satisfied by improving the fodder.
From GB-PS 2 041 403, the preparation of fodder by the biological transformation of waste material of agriculture by means of anaerobic and aerobic fermentation methods is already known. According to this process, the cellulose of comminuted straw and corn stems is decomposed with the help of a cellulase enzyme released by Trichoderma viridae and the so formed glucose is converted into lactic acid.
On the other hand, it is known that the water hyacinth is not useful as a fodder on account of its high mineral content, and that it can be used, at best, for the production of bio-gas (Easley and Shirley (Hyacinth Control Journal 12 (1974), 82-85).